High water (Acqua Alta) returns in Venice (20/11/2018)…
At its worst, in 1966, acqua alta flooded the city with more than a meter of salty lagoon water; more typically, visitors notice water splashing over canal banks or bubbling up through drains in the Piazza San Marco.
Today, subsidence is estimated at 0.5 to 1 mm per year, mostly due to geological factors and compression of the land beneath the city’s millions of wooden pilings.
A larger problem is the rising sea level, which will become an even bigger threat as global warming melts the arctic ice caps.